From 794439183a29102c784484720c3d0b1960b297e6 Mon Sep 17 00:00:00 2001 From: Jakob Stoklund Olesen Date: Wed, 26 Oct 2011 01:47:48 +0000 Subject: [PATCH] Don't use floating point to do an integer's job. This code makes different decisions when compiled into x87 instructions because of different rounding behavior. That caused phase 2/3 miscompares on 32-bit Linux when the phase 1 compiler was built with gcc (using x87), and the phase 2 compiler was built with clang (using SSE). This fixes PR11200. git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@143006 91177308-0d34-0410-b5e6-96231b3b80d8 --- lib/CodeGen/SelectionDAG/SelectionDAGBuilder.cpp | 11 +++++++---- 1 file changed, 7 insertions(+), 4 deletions(-) diff --git a/lib/CodeGen/SelectionDAG/SelectionDAGBuilder.cpp b/lib/CodeGen/SelectionDAG/SelectionDAGBuilder.cpp index 24bd2cde78d..4822da3df9a 100644 --- a/lib/CodeGen/SelectionDAG/SelectionDAGBuilder.cpp +++ b/lib/CodeGen/SelectionDAG/SelectionDAGBuilder.cpp @@ -2034,14 +2034,17 @@ bool SelectionDAGBuilder::handleJTSwitchCase(CaseRec &CR, return false; APInt Range = ComputeRange(First, Last); - double Density = TSize.roundToDouble() / Range.roundToDouble(); - if (Density < 0.4) + // The density is TSize / Range. Require at least 40%. + // It should not be possible for IntTSize to saturate for sane code, but make + // sure we handle Range saturation correctly. + uint64_t IntRange = Range.getLimitedValue(UINT64_MAX/10); + uint64_t IntTSize = TSize.getLimitedValue(UINT64_MAX/10); + if (IntTSize * 10 < IntRange * 4) return false; DEBUG(dbgs() << "Lowering jump table\n" << "First entry: " << First << ". Last entry: " << Last << '\n' - << "Range: " << Range - << ". Size: " << TSize << ". Density: " << Density << "\n\n"); + << "Range: " << Range << ". Size: " << TSize << ".\n\n"); // Get the MachineFunction which holds the current MBB. This is used when // inserting any additional MBBs necessary to represent the switch.